Estudo espectroscópico vibracional de complexos de Ni (II) com os aminoácidos serina, glicina e ácido guanidoacético

• Ano de defesa: 2006
• Autor(a) principal: Ramos, Joanna Maria Teixeira de Azeredo
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Programa de Pós-graduação em Química; Química
• Palavras-chave em Português: Espectroscopia vibracional, Ni (II); Aminoácidos.; Espectros vibracionais; Níquel; Aminoácido; Vibrational spectroscopy; Ni (II), aminoacids.; CNPQ::CIENCIAS EXATAS E DA TERRA::QUIMICA::QUIMICA INORGANICA
• Link de acesso: https://app.uff.br/riuff/handle/1/18956

This dissertation has as purpose to carry out the structural determination and to obtain the complete vibrational assignment of the infrared spectra of the trans-bis (glycino) nickel (II); trans-bis (serinate) nickel (II) complexes, and for the mixed complex guanidinoacetate-serinate nickel (II). The theoretical determinations of the geometrical structures were obtained using the DFT: B3LYP/6-31G and 6-311G procedures based on the functional density theory. For the study of the trans-bis (glicyno) nickel (II) complex, we used also the HF: B3LYP/ 6-311G procedure. With the aid of the obtained geometrical structures, having in mind the vibrational assignments,the next stage was the theoretical determination of the vibrational spectra of these complexes. For the vibrational analysis in the metal-ligands region we propose the study of the distorted geometries generated of each normal mode. Working of such manner we were able to obtain the percentage of deviation of the geometrical parameters in the vibrational mode structure, and from the results of such analysis, we propose the more exact vibrational assignment in the low energy region. From the results we conclude that in the quelato-complexes, such as the studied in this dissertation, the metal-ligand Ni-N and Ni-O stretching, symmetrical or asymmetrical, can not be classified as pure, or with a minor mixture of another normal modes, such as is the case of complexes with single ligands. The stretching Ni-N and Ni-O normal modes, and the bond angle deformation normal modes O-Ni-N, O-Ni-O and N-Ni-N are naturally coupled, and they appears participant with different percentages in the normal mode composition. We conclude also, that was adequate and with physical meaningfully the approach of to avoid the internal coordinates which describe the N-H and C-H stretching and H-NH and H-C-H bending of the analysis of the normal modes pertaining of the low energy region, based on the High/Low Energy Separation.